The purpose of this project is the study of genome structure and function of the Aleutian disease virus (ADV), a nondefective parvovirus of mink. Further studies on this project have included the molecular cloning in pUC8 of a 1.6 kbp segment (0.56-0.86 map units) of a Danish isolate of ADV (DK ADV). This clone, designated pBM2, corresponds to pBM1, the equivalent segment of ADV-G also cloned in pUC8. Comparisons of the DNA's of these two plasmids have been made: 1) heteroduplex mapping by electron microscopy showed the ADV-G and DK ADV segments were the same size and contained no extended areas of heterology, 2) however, physical mapping with restriction enzymes has shown distinct differences. These recombinant plasmids have also been tested for protein expression in E. coli and we found that both pBM1 and pBM2 induce ADV specific products in JM103. Both plasmids induced 55k, 34k, and 27k polypeptides demonstrable by immune "Western" blotting as well as by immunoprecipitation. The interrelationship of the three proteins is under study but preliminary evidence suggested that at least the 27k protein reacts with monoclonal antibodies having specificity for ADV structural proteins. Finally, we have found that ADV DNA from virions purified from mink organs was of unit length and reacted with our ADV recombinant plasmids. Thus, we now have the reagents to begin molecular cloning of DNA from field strains of ADV.